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Abstract

The idea of sourcing for innovative construction Supplementary Cementitious Materials (SCM) in concrete or mortar cannot be overemphasized. Metakaolin has always been used to replace cement in concrete or mortar batching on site. This research investigated the properties of factory produced blended cement using metakaolin obtained from three different sources and consider effects of nanosilica on blended cement mortar. The kaolin clay sourced from Ijero, Ikere, and Isan in Ekiti states were calcined at 700 ˚C for 1 hour and thereafter, characterized using X-Ray Fluorescence Analyser (XRF) and X-Ray Diffraction Analysis (XRD). Ordinary Portland Cement (OPC) clinker and 10% metakaolin were used to produce blended cement. Liquid nanosilica was synthesized from cola pod extract and silica precursor in ratio 1:5. A cement-sand ratio of 1:3 and water/binder ratio of 0.5 were used to produce metakaolin blended cement mortar with addition of nanosilica in varying percentages of 1, 2, 3, 4 and 5% by weight of the binder. The setting times and water demand of the blended cement mortar were determined. The results revealed that the setting times and water demand were observed to reduce as the percentage of nanosilica was increased to a level of 4%. In addition, results of the XRF classified metakaolin as class N pozzolans with the addition of SiO 2 , Al 2 O 3 , Fe 2 O 3 greater than 70%. Also, the SO 3 for all the clay was found to be less than 4% and the peak intensities as reflected on the XRD showing the amorphous nature of the silica.